The presence of dissolved gas in fluid, such as water, under pressure can lead to unacceptable performance of certain support and monitoring equipment in industry. These factors are extremely important in nuclear power plants. In both pressurized water reactors and boiling water reactors, the presence of dissolved gas in reference level pipes for water level detectors leads to outgassing and degradation of calibration. In the case of the water-filled accumulators for an emergency core cooling system, called upper head injection, the presence of substantial amounts of dissolved gas (such as hydrogen and nitrogen) degrades the ability of the system to function and provide emergency core cooling. Dissolved gas is released during rapid pressure reductions which results in expulsion of fluid from reference pipes. This leads to erroneous vessel level readings at a time when there is a critical need for accurate level measurement.
A method and apparatus for measuring the gas content of metal samples is disclosed in U.S. Pat. No. 3,177,700 issued to Sier. A predetermined quantity of inert gas is present and a katarmeter is used to measure the amount of liberated gas using a Wheatstone bridge circuit.
U.S. Pat. No. 4,965,041 issued to Becker discloses an instrument for monitoring the cooling conditions of the reactor core of a nuclear reactor. An electrical resistor is heated and the temperature of the resistor is monitored.
U.S. Pat. No. 3,488,584 issued to Ziniuk discloses a high frequency bridge including a sensing probe disposed in a flowing liquid metal and a second probe in a reference sample of known purity. Thus any difference in electrical resistivity is due to a difference in contamination.
None of these references are directed toward monitoring dissolved gas in a fluid such as water. A need for a simple rapid responding device for monitoring the presence of dissolved gas in a fluid is needed for applications such as in nuclear reactors.